US2150805A - Method of preparing halftone negatives with variable-density screens - Google Patents

Method of preparing halftone negatives with variable-density screens Download PDF

Info

Publication number
US2150805A
US2150805A US140985A US14098537A US2150805A US 2150805 A US2150805 A US 2150805A US 140985 A US140985 A US 140985A US 14098537 A US14098537 A US 14098537A US 2150805 A US2150805 A US 2150805A
Authority
US
United States
Prior art keywords
variable
screen
density
light
layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US140985A
Inventor
Meulendyke Charles Edmund
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US140985A priority Critical patent/US2150805A/en
Application granted granted Critical
Publication of US2150805A publication Critical patent/US2150805A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F5/00—Screening processes; Screens therefor
    • G03F5/14—Screening processes; Screens therefor by contact methods
    • G03F5/16—Screening processes; Screens therefor by contact methods using grey half-tone screens

Definitions

  • This invention relates to new and useful improvements in employing half-tone screens of the variable-density type for making half-tone negatives.
  • the ordinary photo-engraving screen consists of cross-ruled lines. They have black lines and transparent spaces usually of equal width.
  • the transparent spaces 10 may be more or less veiled over, the opaque elements have a low density at the edges of each element and a progressive increase in density in moving across the diameter toward the center of such element.
  • This invention is concerned 15 only with this variable-density type of screen.
  • the preparation of a halftone negative with the normal photo-engraving screen involves considerable skill in camera manipulation.
  • the screen separation must be carefully calculated and various exposures with dif ferent stops are necessary to give the required dot formation.
  • the screen is preferably used as contact screen. The use of this screen will produce correct formation of dots from highlight to shadow without the camera manipulation of screen distance and partial exposures through a series of stops. Further, by controlling the density gradient in the individual elements of the screen, the invention is able to produce screens to take care of copy of different contrasts.
  • a uniform translucent layer interposed between the screen and the light-sensitive layer promotes a wider range of dots in passing from high-light to shadow.
  • the use of such light-diffusing layer is of no advantage with use of the normal photo-engraving screen.
  • the variable-density screen With the variable-density screen, however, I have found the quality of the halftone negative to be considerably enhanced.
  • Such light-difiusing layer may be of any suit- 45 able material. It may be introduced as a translucent support or as a separate layer coated on transparent support. It may be an integral part of the variable-density screen; it may be introduced as a separate element; or preferably it may be introduced as a backing on the negative material to be exposed.
  • a layer of barium sulphate or starch grains in gelatin will make a suitable light-diifusing medium.
  • a A coating of dye or manganese dioxide in gelatin such as used for a nonhalation backing on film is also suitable.
  • the method of producing a half-tone negative including the steps'of passing a light image from a positive through a half-tone screen having uniform elements of variable density, passing the half-tone image thus formed through a uniform translucent layer which per so has light-diffusing properties, and impressing the resultant light image upon a suitably supported light-sensitive layer said screen, translucent layer, and suitably supported light-sensitive layer being in contact during the impression of the image on the latter.
  • the a method of producing a half-tone negative including the steps of passing a light image from a positive through a half-tone screen having uniform photographic elements of variable density, passing the half-tone image thus formed 40 through a uniform translucent layer which per se has light-diffusing properties, impressing the resultant light image upon a suitably supported silver halide emulsion layer said screen, translucent layer, and suitably supported light-sensb tive layer being in contact during the impression of the image on the latter, and developing the emulsion layer.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)

Description

Patented Mar. 14, 1939 UNITED STATES METHOD OF PREPARING HALFTONE NEGATIVES WITH VARIABLE -I)ENSITY SCREENS Charles Edmund Meulendyke, Rochester, N. Y.
No Drawing. Application May 5, 1937, Serial N0. 140,985
2 Claims.
This invention relates to new and useful improvements in employing half-tone screens of the variable-density type for making half-tone negatives.
As is well known, the ordinary photo-engraving screen consists of cross-ruled lines. They have black lines and transparent spaces usually of equal width. In the variable-density screen, on the other hand, while the transparent spaces 10 may be more or less veiled over, the opaque elements have a low density at the edges of each element and a progressive increase in density in moving across the diameter toward the center of such element. This invention is concerned 15 only with this variable-density type of screen.
As is well known the preparation of a halftone negative with the normal photo-engraving screen involves considerable skill in camera manipulation. The screen separation must be carefully calculated and various exposures with dif ferent stops are necessary to give the required dot formation. With the variable-density screen produced by my method, the screen is preferably used as contact screen. The use of this screen will produce correct formation of dots from highlight to shadow without the camera manipulation of screen distance and partial exposures through a series of stops. Further, by controlling the density gradient in the individual elements of the screen, the invention is able to produce screens to take care of copy of different contrasts.
According to my invention I propose a method for making half-tone negatives with improved quality of gradation with use of a variable-density screen. I have found that a uniform translucent layer interposed between the screen and the light-sensitive layer promotes a wider range of dots in passing from high-light to shadow. The use of such light-diffusing layer is of no advantage with use of the normal photo-engraving screen. With the variable-density screen, however, I have found the quality of the halftone negative to be considerably enhanced.
Such light-difiusing layer may be of any suit- 45 able material. It may be introduced as a translucent support or as a separate layer coated on transparent support. It may be an integral part of the variable-density screen; it may be introduced as a separate element; or preferably it may be introduced as a backing on the negative material to be exposed. A layer of barium sulphate or starch grains in gelatin will make a suitable light-diifusing medium. a A coating of dye or manganese dioxide in gelatin such as used for a nonhalation backing on film is also suitable. In producing a laterally reversed half-tone negative by exposing through a variable-density screen and through the nonhalation backing of a commercial offset film, I have found such exposure to yield a much better dot gradation than will be yielded by unbacked film under the same conditions of exposure.
It will thus be seen that I have described processes with all necessary details embodying the principles and attaining the objects and advantages of the invention. Since many matters of treatment, manipulation, selection of materials, succession of steps, and other details may be variously modified without departing from the principles involved, I do not intend any limitation to such details excepting so far as set forth in the appended claims.
What is claimed is:
1. In the art of photo-mechanical printing, the method of producing a half-tone negative including the steps'of passing a light image from a positive through a half-tone screen having uniform elements of variable density, passing the half-tone image thus formed through a uniform translucent layer which per so has light-diffusing properties, and impressing the resultant light image upon a suitably supported light-sensitive layer said screen, translucent layer, and suitably supported light-sensitive layer being in contact during the impression of the image on the latter.
2. In the art of photo-mechanical printing, the a method of producing a half-tone negative including the steps of passing a light image from a positive through a half-tone screen having uniform photographic elements of variable density, passing the half-tone image thus formed 40 through a uniform translucent layer which per se has light-diffusing properties, impressing the resultant light image upon a suitably supported silver halide emulsion layer said screen, translucent layer, and suitably supported light-sensb tive layer being in contact during the impression of the image on the latter, and developing the emulsion layer.
CHARLES EDMUND MEULENDYKE.
US140985A 1937-05-05 1937-05-05 Method of preparing halftone negatives with variable-density screens Expired - Lifetime US2150805A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US140985A US2150805A (en) 1937-05-05 1937-05-05 Method of preparing halftone negatives with variable-density screens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US140985A US2150805A (en) 1937-05-05 1937-05-05 Method of preparing halftone negatives with variable-density screens

Publications (1)

Publication Number Publication Date
US2150805A true US2150805A (en) 1939-03-14

Family

ID=22493644

Family Applications (1)

Application Number Title Priority Date Filing Date
US140985A Expired - Lifetime US2150805A (en) 1937-05-05 1937-05-05 Method of preparing halftone negatives with variable-density screens

Country Status (1)

Country Link
US (1) US2150805A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2643188A (en) * 1949-01-13 1953-06-23 Herman E Meyer Method of preparing a photographic three-dimensional grain screen and for producing a photographic dry plate having a latent threedimensional screen pattern thereon
US2692198A (en) * 1950-08-11 1954-10-19 Maurice D Whitney Methods of producing half-tone printing plates
US3122436A (en) * 1958-06-11 1964-02-25 Francis E Wattier Making rotogravure cylinders or plates
WO1981001886A1 (en) * 1979-12-31 1981-07-09 Ncr Co Method and apparatus for fabricating a translucent graded density medium

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2643188A (en) * 1949-01-13 1953-06-23 Herman E Meyer Method of preparing a photographic three-dimensional grain screen and for producing a photographic dry plate having a latent threedimensional screen pattern thereon
US2692198A (en) * 1950-08-11 1954-10-19 Maurice D Whitney Methods of producing half-tone printing plates
US3122436A (en) * 1958-06-11 1964-02-25 Francis E Wattier Making rotogravure cylinders or plates
WO1981001886A1 (en) * 1979-12-31 1981-07-09 Ncr Co Method and apparatus for fabricating a translucent graded density medium
US4284715A (en) * 1979-12-31 1981-08-18 Ncr Corporation Method and apparatus for fabricating a translucent graded density membrane

Similar Documents

Publication Publication Date Title
US2455849A (en) Photographic unsharp masking method
US2691585A (en) Prescreened posterizing photographic film
GB544033A (en) Improvements in or relating to half-tone screens for photomechanical printing processes
US2150805A (en) Method of preparing halftone negatives with variable-density screens
US2767093A (en) Photo printing process
US3442648A (en) Photographic dodging method
US3977872A (en) Process for the production of negative continuous-tone images
US2628903A (en) Preparation of printing plates and cylinders with chloro-bromide resist-forming film
US1896567A (en) Screen for photographic purposes, photomechanical printing processes and the like
US2691580A (en) Increasing contrast of halftone reproductions
US1804727A (en) Photography
US2176303A (en) Sound track on colored film and method of producing same
US2912325A (en) Light-sensitive film prescreened by herschel exposure
US2102021A (en) Photographic half-tone screen material and process
US1563499A (en) Process of producing true gradation prints for making halftone printing plates
US2339482A (en) Process of producing halftone mask negatives
US2095909A (en) Universal screen for preparing half tones
US1995958A (en) Universal screen for preparing half-tones
US3676122A (en) Process for the production of negative or positive continuous-tone or screened images thereof
US2095015A (en) Manufacture of half tone screens
US1957433A (en) Method of making a photographic printing plate
US2373489A (en) Halftone photoengraving process
US1161824A (en) Photographic screen for half-tone work.
US2588615A (en) Printing onto lenticular film
US2691583A (en) Prescreened photographic film employing albert reversal